Indigo plant

The leaves of the indigo plant do not contain the dye as such, but in the form of its precursor, a glycoside known as indican (109). Indican [487-60-5] is the dextrose derivative (35) of indoxyl [480-93-3] (110). Indoxyl occurs also in the urine of humans as the potassium salt of indoxyl sulfonic acid (111). 

The indigo plant was used as early as 3000 BCE to make purple dyes. For many years humans used insects, snails, and plants to make dyes of bright red, deep red, purple, brown, yellow, and black. The processes of extracting the dyes were expensive. Only the wealthy, and primarily royalty at this early time in history, could afford the deep purple dyes for their clothing and robes. Thus, the tradition of purple as the color of kings was originated. 

In the period 1700 to 1900, the production of what came to be known as natural indigo was carried out on a very large scale. The indigo plant was cultivated in enormous plantations, chiefly in India and the countries of South-East Asia and America. As much as one square kilometer was needed to obtain a tonne of indigo a year [2], The reason for such a high land requirement was simply that the plant material contains barely 1 % of the dye s precursor indican, the rest being biomass. 

Indirubine is formed from the primary indigo of the indigo plants to an increased degree when fermented indigo plants are applied in a relatively weak alkaline vat for dyeing. This situation seems to have been the case with the dark blue threads of the Peruvian sample. 

The increase in the production of the synthetic indigo has decreased the cultivation of the indigo plant, especially in India where the land formerly used for this purpose is now used for other crops such as rubber, turmeric, hemp, cotton, etc. 

Unverdorben, O. (1806-1873) first discovered aniline in 1826, following a dry and destructive distillation of indigo plant and called it crystalline, due to the fact that his new compound easily produced crystals with acids10. 

A few years later, Fritzsche, C. J., (1808-1871) isolated in 1840 the same oil when distilling indigo in the presence of a potassium base, and called it aniline. The latter was named after an indigo-yielding plant Indigofera anil, but also after the Arabic term al-nil, which means indigo13, and the Sanskrit terms ntla (dark-blue) and mid (indigo plant). 

The indigo plant cultivated in India is sown, as seed, in February and, by August, has grown to a height of about 3 feet, at which stage the yield of the dye has reached its maximum of about 0-4 per cent of the weight of the plant, and the crop is harvested. The sap extracted from the plants is... 

Chuck Adamson built a new indigo plant at a cost of 2 million to capitalize on the worldwide craze for blue denim. He managed to convince the IRS that the craze would last only two years so that he should be able to depreciate the plant in 2 years by straight line, even though the plant will physically last 15 years. Let s assume the blue denim craze continued strongly into the third year. Will Adamson operate without a plant listed on the balance sheet Will he have no capital depreciation expenses on his product cost Can he undersell any would-be newcomers into the market ... 

USE For dyeing hair and nails auburn to red, in the Orient together with " rang, the dried, powdered Leaves of the indigo plant, in order to produce darker and even bluish-black shades. For relatively permanent dyeing the pH must be about 5.5 this is achieved by the addition of citric, boric, or adipic acid. Ingredient of many commercial hair rinses. 

Indigo blue is an insoluble blue substance obtained from the indigo plant. When it comes in contact with reducing agents some of which... 

Figure 7. Tropical indigo manufactory, 1694 (A) the white overseer (B) cutting the indigo plant (C) infusing it in water (D) carrying away...

C7H,5N30j, Mr 173.22, monohydrate of the monohydrochloride, mp. 131-134 °C, [a]p +18° (5 M HCl). A toxic amino acid from the creeping indigo plant (7n-digofera spicata) and related species (Fabaceae)It is hepatotoxic and teratogenic, potently inhibits the ami-noacylation of arginine, and is a competitive inhibitor of arginase. It also prevents the incorporation of thymidine in the DNA in cultured human red blood cells. For synthesis, see Lit.. ... 

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